How to pick a watermelon?

Look for yellow spots on the watermelon. Since the fruit rests on the ground after ripening, it causes them to develop yellow spots that indicate the watermelon is ripe. Tap it with your finger, if the sound is hollow, it means the watermelon is ripe, and if not, it is not perfectly ripe. If the watermelon is heavy as compared to its size, it is a sign that the watermelon is ripe.